(Reuters) - Tesla Inc’s (TSLA.O) board has not yet received a detailed financing plan from CEO Elon Musk, and is seeking more information about how he will take the U.S. electric car maker private in a proposed deal worth $72 billion, people familiar with the matter said on Thursday.

While Tesla’s board has held multiple discussions about Musk’s proposal, which first became public on Tuesday, it has not yet received specific information on who will provide the funding, one of the sources said.

Tesla declined to comment.

Musk, a 47-year-old investor and engineer, stunned financial markets on Tuesday, when he revealed on Twitter he was considering a take-private deal for Tesla, an auto manufacturing pioneer that developed the world’s first ever premium all-electric sedan car.

The move came after months of Musk battling investors, journalists and analysts over whether Tesla could turn a profit and produce enough of the mass market model of is flagship electric car to meet demand.

Musk said in a tweet on Tuesday that he had secured financing for the deal, but he did not publicly provide further details.

Speculation has swirled among shareholders and investment bankers about who could fund a deal of that size, especially given that the company’s bonds are already rated junk by credit rating agencies.

The U.S. Securities and Exchange Commission has contacted Tesla to ask about Musk’s assertion on Twitter that funding for his proposed deal was “secured”, the Wall Street Journal reported on Wednesday.

The revelation that the board is seeking more details from Musk could raise new questions about how he plans to finance the deal at his proposed price of $420 per share.

After jumping to close at $379.57 on Tuesday, Tesla shares have since fallen about 7 percent to end trading at $352.45 on Thursday, amid investor skepticism over the deal’s prospects.

In a statement on Wednesday, Tesla’s board said its discussion with Musk “addressed the funding” for the deal, without offering more details.

The board expects to make a decision on whether to launch a formal review of Musk’s proposal in the coming days, and is speaking to investment bankers about hiring financial advisers to assist it in its review in such scenario, the sources said.

If the board launches a formal review of Musk’s bid, he would have to recuse himself, or a special board committee would have to be formed, according to the sources, who requested anonymity because the deliberations are confidential.

The exact information that Musk communicated to the board about his plan could not be learned.

Taking Tesla private would remove the pressure from Musk coming from hedge funds betting that the company’s stock will drop given its production issues and negative cash flow, as well as the glare of Wall Street that comes with reporting quarterly earnings publicly.

The company faces a make-or-break moment in its eight-year history as a public company as competition from European automakers is poised to intensify with new electric vehicles from Audi and Jaguar, with more rivals entering the market next year.

Tesla is still working its way out of what Musk called “production hell” at its home factory in Fremont, California, where a series of manufacturing challenges delayed the ramp-up of production of its new Model 3 sedan on which the company’s profitability rests.

Meanwhile, Tesla has announced plans to build a factory in Shanghai, China, and another in Europe, but details are scarce and funding unknown.

DIFFICULT TO FINANCE

Musk has said he would be looking to keep his ownership of Tesla at around 20 percent in a buyout deal, and that a special purpose vehicle, like the one that exists at his aerospace company SpaceX, would allow Tesla shareholders to remain invested if they so choose.

Investment bankers and analysts have reacted with skepticism, telling Reuters it would be hard for Musk, whose net worth is pegged by Forbes at $22 billion, to raise the equity and debt financing needed for the deal given Tesla is not turning a profit.

Some analysts have suggested that Musk could convince Tesla’s top shareholders, such as Fidelity Investments and China’s Tencent, to roll their equity stakes into the deal, thereby significantly reducing the amount of money needed to be raised.

FILE PHOTO: Elon Musk, founder, CEO and lead designer at SpaceX and co-founder of Tesla, speaks at the International Space Station Research and Development Conference in Washington, U.S., July 19, 2017. REUTERS/Aaron P. Bernstein/File Photo

However, the deal structure would come with big logistical and legal challenges when it comes to buying out smaller shareholders, analysts have said.

Saudi Arabia’s Public Investment Fund (PIF) has taken a stake of less than 5 percent in Tesla, a source familiar with the matter said on Tuesday. It is not clear if PIF is interested in financing Musk’s proposed take-private deal.

Reporting by Carl O'Donnell and Liana B. Baker in New York; editing by Clive McKeef